A.M. Best Co. has assigned debt ratings of “bbb+” to the $250
million 3.625% senior unsecured notes due 2023 and the $250 million 5.0%
senior unsecured notes due 2043, issued under the existing shelf
registration of Markel Corporation (Markel) (Richmond, VA) [NYSE:
MKL]. The outlook assigned to both ratings is stable.

Markel will use the net proceeds from the sale of the notes for general
corporate, including acquisitions.

After the close of the Alterra Capital Holdings Limited [NASDAQ:
ALTE] transaction, which is expected in second quarter 2013, Markel’s
total debt-to-capital ratio is projected to be at a manageable 27%,
increasing to 34% when debt is measured to tangible equity. At December
31, 2012, Markel's stand-alone debt leverage was 28%. Markel’s financial
leverage and coverage ratios remain within A.M. Best’s guidelines for
its debt ratings.

At the holding company level, Markel will have pro-forma cash and
investments in excess of $1.0 billion, affording it a significant level
of liquidity.

The methodology used in determining these ratings is Best’s Credit
Rating Methodology, which provides a comprehensive explanation of A.M.
Best’s rating process and contains the different rating criteria
employed in the rating process. Best’s Credit Rating Methodology can be
found at www.ambest.com/ratings/methodology.

Founded in 1899, A.M. Best Company is the world’s oldest and most
authoritative insurance rating and information source. For more
information, visit www.ambest.com.